Method of making insulated hose clamps



y 1965 J. c. CRAWFORD, JR., ETAL 3,196,535

METHOD OF MAKING INSULATED HOSE CLAMPS Original Filed Nov. 12, 1958 2Sheets-Sheet l y 1965 J. c. CRAWFORD, JR, ETAL 3,196,535

METHOD OF MAKING INSULATED HOSE CLAMPS 2 Sheets-Sheet 2 Original FiledNov. 12, 1958 INVENTOR.

(TAMI-1s C.CRAwFoRD,Jh. Y RALF L.HARTWELL ATTORNEY 3,196,535 METHUD 6FMAKING ENSULATED HQSE CLAMES (C. fl'awferd, in, White Plains, N.Y., andRalf L. Hartwell, Cranial-d, NJL, assignors to .lohns-Manviilegorgfiloration, New York, NY, a corporation of New or Originalapplication Nov. 12, 195$, Ser. No. 773,474, new latent No. 3,139,253,dated June 30, 1964.. Divided and this application May 31, 1962, Ser.No. 216,940 2 Claims. (Cl. 29-446) This invention relates to a clamp forholding various types of conduits and to the method of making such aclamp. More specifically, the invention provides a metal clamp with aresilient cushion of insulating material secured thereto for holdingconduits or ducts in areas of extremely high temperatures, approximately200W R, and subjected to excessive vibrations. Such clamgs areparticularly suited for installation in aircraft, space travelingvehicles or projectiles, and the like, but are also intended for use inany desirable surroundings. This application is a division of ourcopending application Serial No. 773,474, filed November 12, 1958, andnow Patent No. 3,139,253.

The general form of metal clamp for tlese purposes comprises a metalband or strip formed into a loop. To allow for dimensionalirregularities and for the dampening of vibrations, the metal band orstrip is encompassed with a resilient cushion. However, for hightemperature operations, in the neighborhood of 2000 F, most cushions arenot satisfactory. When high temperatures are to be encountered, it hasbeen proposed to use material having high insulating qualities such as asuitably sized braided asbestos. However, such material rapidlydeteriorates under the combination of high temperature and excessivevibration and begins to lose its structural integrity and flake off.Also, in aircraft installations, whenever the cushioning material isnon-conductive, it is necessary to provide a bonding strip that willcooperate with the metal band or strip to equalize the potential betweenthe air frame and the conduit to prevent static discharges whichinterfere with radio transmission and reception.

It is an object of this invention to provide a clamp for holdingconduits in which the clamp is resistant to excessive vibration and hightemperature.

lt is another object of this invention to provide a method for making aclamp for holding conduits in a desired position in which the clamp isprovided with a heat resistant cushion.

It is a further object of this invention to provide a clamp for holdingconduits in a desired position wherein the clamp is provided with ameans for holding a heat resistant cushion in position on a metal stripand wherein said means also provides for equalizing the electricpotential between the supporting structure and the conduit.

The foregoing objects are preferably accomplished in accordance with theinstant invention by a metal clamp having a refractory felt secured tothe metal clamp so that the refractory fi er felt forms an insulatingcushion on the inner surface or" the clamp and is adapted to contact theconduit and to be held in position when the clamp is'formed into a loop.In the prefercd embodiment of the invention, the insulating cushion isdesigned to retain the intc rity of the fibers in the insulating cushionand yet has suflicient flexibility so that the insulating cushion mayreadily conform to the inner contour of the loop forming the metalclamp. Furthermore, in the preferred embodiment, the insulating cushionencased in the flexible mesh envelope is secured to a pre-formed metalstrip of the clamp by a second flexible mesh envelope that encases thepro-formed metal strip and the insulating cushion and is secured to thepro-formed metal strip by weld- United States Patent 0 ing through anencircling retaining band. The second mesh envelope is preferably ofheavier construction to protect the structure against abrasion and isalso adaptable for bending within the radius of the metal strip withoutbuckling. However it is to be understood that the invention is not to belimited to the preferred embodiment or to the forms illustrated anddescribed in the following specification.

The preferred method for making the preferred clamp of the instantinvention .is to insert an insulating cushion encased in a firstflexible mesh envelope within a relative- 1 large second mesh envelopewhich fits loosely around the first flexible mesh encased insulatingcushion. The free end of a preformed metal strip is inserted between thesecond flexible mesh envelope and the first flexible mesh encasedinsulating cushion. Suitable tension is applied to the second envelopeto stretch the second envelope along its longitudinal axis to a narrowerwidth and a smaller stitch opening so that the second flexible meshenvelope snugly encases the metal strip and the flexible mesh enclosedinsulating cushion. The second flexible mesh envelope is secured to themetal strip adjacent to but spaced from each end of the strip byresistance welding through an encircling retaining band and theremaining ends of the second flexible mesh envelope are severed forremoval. In other forms of the instant invention, various appropriatemethods are used for securing the flexible mesh enclosed insulatingcushion to the metal strip which is pro-formed into a loop.

The invention will be more fully understood and further objects andadvantages thereof will become apparent when reference is made to thefollowing detailed description of various embodiments of the inventionand the accompanying drawings in which:

FZGS. 1 through 3 illustrate a method for enclosing an insulatingcushion within a flexible mesh envelope;

FIG. 4 is a view with parts broken away to show a flexible mesh encasedinsulating cushion loosely within an open second flexible mesh envelope;

FIG. 5 is a view with part of one end of the open second mesh envelopebroken away and illustrating the insertion of the end of a preformedclamp between the flexible mesh ncased insulating cushion and the opensecond flexible mesh envelope;

FIG. 6 is a view showing the final portion of the assembly with thetension being applied to the other end of the second flexible meshenvelope;

FIG. 7 is a pictorial representation of a clamp made in accordance withthe instant invention;

FIG. 8 is a view in cross-section showing the preferred embodiment ofthe clamp of the instant invention;

FIG. 9 is a view in cross-section of another type' clamp made inaccordance with the instant invention;

FIG. 10 is a view in cross-section of another type of clamp made inaccordance with the instant invention; and

FIG. 11 is a view in cross-section of a part of another type of clampmade in accordance with the instant invention.

Referring to the drawings, there is illustrated in FIGS. 1-3 the methodfor encasing an insulating cushion 1 within a flexible metal meshenvelope 2. The insulating cushion 1 is placed within an open endedtubular metal mesh envelope 2 which, as illustrated in FIG. 1, is ofsufficient tubular size in cross-section to receive loosely theinsulating cushion 1. As shown in FIG. 1, the tubular mesh envelope 2has a relatively open stitch 3. When the insulating cushion 1 is withinthe mesh envelope 2, a tension is applied to the ends 4 of the meshenvelope 2 by the jaws 5 so that the flexible mesh envelope 2 isstretched along its longitudinal axis. As the mesh envelope 2 isstretched, the lateral size or width of the stitch opening 3 decreasesas a comparison of FIGS.

1 and 2 readily indicates. When the mesh envelope 2 has been stretched adistance, which may be predetermined, so that the mesh envelope iscontiguous to the insulating cushion 1, the adjacent ends of the meshenvelope 2 are subjected to the resistance welding tips 6 and securedtogether to form a flexible mesh closure around the insulatingcushion 1. In the product illustrated in FIG. 3, the insulating cushion1 is a refractory fiber felt and is enclosed in a flexible knitted wireInconel envelope. However, it is to be appreciated that the insulatingcushion can be made of any desired insulating material, having similarphysical characteristics, and the flexible mesh envelope could also bemade of other suitable material.

. The method of securing a flexible mesh enclosed insulating cushion toa metal strip 8 which is pre-formed into a loop to form a clamp forholding 'a conduit in a desired location is illustrated in FIGS. 4-6.

An insulating cushion l'enclose'd in a flexible mesh tions of theconduits 16 are dampened thereby. The

clamp thus functions to hold the conduit 16 in a desired position andtoprovide dampening action with high heatresistant characteristics, asprovided, for example, when a pad of felted refractory fiber is employedas the insulatenvelope 2 is inserted within a second open ended tubularI flexible mesh envelope 9 which loosely receives the flexible meshencased insulating cushion 1, 'as' illustrated in FIG. 4. The free end8a of the pre-formed metal strip 8,

as shown in FIG. 5, is inserted between the flexible mesh encasedinsulating cushion. 1 and the second open ended,

tubular, flexible mesh envelope 9 and the relative move ment between thepre-formed metal strip'8 and the flexible mesh encasedin-sulatingcushion' 1 and the second trated in FIG. 6, with the end'.9aof'the flexiblemesh envelope 9 extending. slightly beyond the end of theflexible mesh encased insulating cushion 1. The end 9a is then securedto the prei-formed strip 8 bylwelding. The

end of the flexible mesh encased insulating cushion 1 adjacent the innersurface of the metal strip 8 near the area ,8b thereof is held inposition by any manner, such as by "hand, and tension is then applied tothe free other end of the mesh envelope 9 by the jaws 5 so that thetubular mesh envelope 9 is stretched along its longitudinal axis, As themesh envelope 9 is stretched, the lateral size or width of the stitchopening decreases asa comparison of FIGS. 5 and 6 readily indicates; Thetubular mesh envelope 9 is stretched a distance, which'may. be

predetermined, until it is in contiguous relationship with the metalstrip 8 and the flexiblemeshenclosed insulating ing cushion-1. The clampillustrated in FIG. 7 may be formed by the method-described-aboverelative to FIGS. 46, inclusive, except that the insulating cushion isnot encased within a first flexible mesh envelope before being retainedin position onthe metal strip 8.

V The preferred: embodiment of the instant invention is illustrated inFIG; 8 which shows a clamp made in accordance with the methodillustrated in FIGS. 4-6. An insulating cushion 1, as previouslydescribed, is enclosed in a flexible mesh envelope 2 and is placed insuperposed relationship on ametal strip 8. The enclosed insulatingcushion is secured in proper position on the inner surface .of the loopformed by the metal strip 8 by another flexible mesh envelope 9 which issecured to the metal strip 8 by the metal bands lfl which are weldedthereto. If desired the ends of the mesh envelope 9 may be secured tothe metal strip 8 by weldingbefore the bands'10, are applied. A bolt 14passes through aligned openings 18 in the ends 11' and 12 and isthreadedly secured in the supporting structure 15. Theiclamp illustratedin FIG. 8

tions of the conduit 16 are dampened thereby. The

clamp thus functions to hold the conduit 16 in a desired position and toprovide dampening action with high heatresistant characteristics. 1 p

In FIG. 9, there is illustrated a form of the instant invention similarto that of FIG. 8. To protect further the insulatingjcushion 1, a stripof thin'heat-resistant foil 19 is inserted between the mesh envelopes 2and. 9. This foil 19 functions to serve as a solid barrier against anytendency of the insulating cushion to flake out due to vibration. Ifdesired, the foil 19 could contain transverse corrugations, atright'angles to the length thereof, and of a suitable depth and pitch toprevent buckling when formed into a loop. The remainder of the structureand its function is in accordance with that described in connectionwiththe clamp of FIG. 8.

In the form of the invention illustrated in FIG. 10, an

1 .insulating cushion 1 enclosed in a flexible mesh envelope cushion 1..As illustrated in FIG. 8,'the flexible mesh envelope 9 is now holdingthe flexible mesh'encased in- 1 sulating cushion l adjacent' the innersurfiace'of themetal' strip 8. The section of the mesh envelope 9extending beyond the insulating cushion 1 is secured, as by welding,

adjacent the end So of the pre-formed metal strip '8',

and the remaining portion of the mesh envelope is severed. A metal band10 encircles each end of the tubular mesh envelope 9 and is subjected tothe resistance welding tips 6 to secure further the insulating cushion 1in proper position on the metal strip 8.

In the form of the invention illustrated in FIG} 7, a metal strip 8 hasbeen bent intojsubs'tant'ially a loop with its end portions 11 and 12 inmating superposed relationship. An insulating-cushion 1 is secured inposition on the inner surface of the loop formed by the'metal strip 8 bya flexible mesh envelope 2 by. a method similar to that described inrelation to FIGS. 4-6, inclusive, and the metal strip 8. A bolt 14passes throughaligned openings in the ends 11 and ,12 and is threadedsecured in the sup- 2 is secured in position on the inner surface of theloop formed by the metal strip 8 by a flexible heat-resistant foil strip21. The foil striprz l has a plurality of transverse corrugations 22, atright angles to the length thereof, which are of suitabledepth and pitchto prevent buckling when formed into the loop. The ,ends 23 and 24 ofthe foil strip 21 are secured to the metal strip 8 by,welds 25." Inoperation, the conduit 16 is snugly received Within the encircling foilstrip 21 so that the insulating cushion willdampen any vibrations and isheld in desired position by the bolt 14 passing through aligned openings18 in the .ends 11 and 12 in the metal strip 8 and'threadedly receivedin the supporting structurelS.

The foil strip 21' serves as .a solid barrier against any tendency ofthe insulating cushion to flake out due to vibration. The foil' mightalso be extended around the edges of the insulating cushion 1 enclosedby the mesh 2 to provide still more complete protection from hot andcorrosive gases, provided the foil issufliciently flexible or isrendered sufiiciently flexible by crimping, corrugating,

7 similar to that illustrated in FIG. 10. A second heatresistantcorrugated foil strip 27 is positioned between the flexible meshenclosed insulating cushion 1 and the metal strip 8. The corrugated foilstrip 27 functions to allow cooling air to pass between the insulatingcushion 1 and the metal strip 8. The clamp, illustrated in FIG. 11,functions to hold a conduit 16 in a desired position as explained inconnection with the other forms of the invention, particularly thatillustrated in FIG. 10.

in the forms of the invention illustrated herein, the insulating cushionwas formed from a refractory fiber felt A3 in thickness, such as thatmarketed under the trademark Thermoflex RIF-1200, and capable ofwithstanding temperatures to 2000 F. The tubular flexible mesh envelopeswere made of knitted Inconel wire and had the characteristic of beingreadily adaptable to be stretched to a narrower width and a smallerstitch opening upon applying suitable tension along the longitudinalaxis thereof. The heat-resistant foil strips disclosed herein were madefrom sheets of .004 Inconel metal cut to a predetermined length and thencorrugated, in the forms of the invention in which corrugations wereemployed. The metal strips 8 forming the main body of the clamp were ofstandard design and shape, and adapted to Withstand high temperatures inservice. It is to be noted that the particulars given above are forillustration purposes only, and it is not intended to limit theinvention thereto.

in operation, the instant invention provides a clamp for conduits inwhich the insulating cushion 1 functions as a resilient cushion capableof absorbing excessive vibration and at the same time possessing highlydesirable high heat-resistant characteristics. The flexible meshenvelope retains the effective structural integrity of the insulatingcushion and yet has sufficient flexibility to permit bending to conformto the desired contour of the clamp. In the preferred form of theinvention, that illustrated in FIG. 8, the heavier outer mesh envelopeserves to protect the structure against abrasion in addition to theother desired prevailing characteristics. The clamp provided by theinstant invention cushions or dampens local vibrations without causingundue stresses in the supporting structure. Also, in the forms of theinvention illustrated in the drawing, the clamp is provided with a metalsurface in contact with the conduit so that it may serve as anelectrical conductor, whether or not the insulating cushion itself willso function, for the purpose of equalizing the potential between thesupporting structure and the conduit to prevent static discharges and inproviding any other desired electrical property.

The insulated clamp of the instant invention possesses other highlydesired characteristics. The insulating cushion of a refractory fiberfelt is of itself heat-resistant and at the same time has a resilientnature to hold securely a. conduit while dampening the excessivevibration thereof. The resiliency of the insulating cushion and thestretch of the flexible mesh envelope allows for the expansion of theconduit due to the heat of the surroundings. Thus, as the conduitexpands to a greater diameter, the resiliency of the insulating cushionwill absorb the expansion of the conduit without undue binding of theclamp on the conduit, such binding being undesirable as it tends toprevent the normal relative longitudinal movement between the clamp andthe conduit which occurs upon expansion and contraction of the conduit.

Having thus described the invention in rather full detail, it will beunderstood that these details need not be strictly adhered to andthatvarious changes and modifications may suggest themselves to one skilledin the art, all falling within the scope of the invention as defined bythe subjoined claims.

What we claim is:

1. A method for making a heat and vibration-resistant clarnp for holdingconduits in a desired location comprising:

(a) positioning an insulating cushion within a loosely fitting,open-ended, tubular, knitted wire, mesh envelope,

(b) said insulating cushion comprising a heat-resistant material adaptedto dampen vibrations,

(c) inserting one end of a preformed metal strip having end portions andan intermediate portion, preformed into a loop corresponding to theshape of the conduit to be held, between said insulating cushion andsaid tubular, knitted wire, mesh envelope,

(d) positioning said insulating cushion and said tubular, knitted Wire,mesh envelope relative to said preformed metal strip by relativemovement between said metal strip and said insulating cushion and saidtubular, knitted wire, mesh envelope so that said insulating cushionforms a second loop having a radius of curvature smaller than said firstloop and said tubular, knitted wire, mesh envelope surrounds saidinsulating cushion and said metal strip,

(e) securing one end of said tubular, knitted wire,

mesh envelope to said preformed metal strip adjacent but spaced from theother end of said preformed metal strip,

(f) applying tension to the other end of said tubular, knitted wire,mesh envelope to stretch said tubular, knitted wire, mesh envelope alongits longitudinal axis while holding said insulating cushion in positionadjacent the inner peripheral surface of said loop portion of said metalstrip,

(g) stretching said tubular, knitted wire, mesh envelope to reduce thelongitudinal cross-sectional configuration thereof until it iscontiguous to the inner surface of said insulating cushion and the outersurface of said preformed metal strip,

(h) securing the stretched tubular, knitted wire, mesh envelope to saidpreformed metal strip adjacent but spaced from said one end of saidpreformed metal strip, and

(i) severing the remaining portion of said stretched tubular, knittedwire, mesh envelope.

2. A method for making a heat and vibration-resistant clamp for holdingconduits in a desired location comprising:

(a) encasing an insulating cushion within a tubular, knitted wire, meshenvelope with said tubular, knitted wire, mesh envelope being contiguousthereto,

(b) said encased insulating cushion comprising a heatresistant materialadapted to dampen vibrations, (c) positioning said encased insulatingcushion within a loosely fitting, open-ended, tubular, knitted wire,

mesh envelope,

(d) inserting one end of a preformed metal strip havend portions and anintermediate portion, preformed into a loop corresponding to the shapeof the conduit to be held, between said encased insulating cushion andsaid tubular, knitted wire, mesh envelope,

(e) positioning said encased insulating cushion and said tubular,knitted wire, mesh envelope relative to said preformed metal strip byrelative movement between said metal strip and said encased insulatingcushion and said tubular, knitted wire, mesh envelope so that saidencased insulating cushion forms a second loop having a radius ofcurvature smaller than said first loop and said tubular, knitted wire, 1.esh envelope surrounds said encased insulating cushion and said metalstrip,

(f) securing one end of said tubular, knitted wire,

mesh envelope to said preformed metal strip adjacent but spaced from theother end of said preformed metal stri (g) applying tension to the otherend of said tubular, knitted wire, mesh envelope to stretch saidtubular, knitted wire, mesh envelope along its longitudinal axis whileholding said encased insulating cushion in position adjacent the innerperipheral surface of said loop portion of said metal strip,

(h) stretching said tubular rknitted wire, mesh enve- (j) severing theremaining portion of said stretched lope to reduce the longitudinalcross-sectional con- 7 tubular, knitted wire, mesh envelope.

figuration thereof until it is. Contiguous to the inner surface of saidencased insulating cushion and the References Cited by the Examinerouter surface of said preformed metal strip, 5 i H UNHED STATES PATENTS'(i) securingthe stretched tubular, knitted wire, mesh 2,908,123, 10/ 59Muller et a1 5337 X envelope to said preformed metal strip adjacent but2,923,760 2/60 iFamely 248-74 X spaced from said one end of saidpreformed rnetal 1/ 62 Schmitt a 10 JOHNVF. CAMPBELL, Primary Examiner.

1. A METHOF FOR MAKING A HEAT AND VIBRATION-RESISTANTI CLAMP FOR HOLDINGCONDUITS IN A DESIRED LOCATION COMPRISINT: (A) POSITIONING AN INSULATINGCUSHION WITHIN A LOOSELY FITTING OPEN-ENDED, TUBULAR, KNITTED WIRE, MESHENVELOPE, (B) SAID INSULATING CUSHION COMPRISING A HEAT-RESISTANDMATERIAL ADAPTED TO DAMPEN VIBRATIONS, (C) INSERTING ONE END OF APREFORMED METAL STRIP HAVING END PORTIONS AND AN INTERMEDIATE PORTION,PREFORMED INTO A LOOP CORRESPONDING TO THE SHAPE OF THE CONDUIT TO BEHELD, BETWEEN SAID INSULATING CUSHION AND SAID TUBULAR, KNITTED WIRE,MESH ENVELOPE, (D) POSITIONING SAID INSULATING CUSHION AND SAID TOBULAR,KNITTED WIRE, MESH ENVELOPE RELATIVE TO SAID PERFORMED METAL STRIP BYRELATIVE MOVEMENT BETWEEN SAID METAL STRIP AND SAID INSULATING CUSHIONAND SAID TUBULAR, KNITTED WIRE, MESH ENVELOPE SO THAT SAID INSULATINGCUSHION FORMS A SECOND LOOP HAVING A RADIUS OF CURVATURE SMALLER THANSAID FIRST LOOP AND SAID TUBULAR, KNITTED WIRE, MESH ENVELOPE SURROUNDSSAID INSULATING CUSHION AND SAID METAL STRIP, (E) SECURING ONE END OFSAID TUBULAR, KNITTED WIRE, MESH ENVELOPE TO SAID PREFORMED METAL STRIPADJA-